A metal plate made of aluminum alloy is disclosed in TW Pub. No. 1380914 and contains a plurality of finely concaved holes, and an adhesive is used to stick plural wooden sheets with the metal plate. Since the adhesive penetrates into the plurality of finely concaved holes to stick the metal plate and the plural wooden sheets together, the sticking force is not strong enough. Hence, the metal plate removes from the plural wooden sheets easily.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.